from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt
from passlib.context import CryptContext
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.orm import Session
from app.core.config import settings
from app.core.database import get_db
from app.models.user import User

# 密码加密
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

# OAuth2 配置
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="api/auth/login")

def verify_password(plain_password: str, hashed_password: str) -> bool:
    """验证密码"""
    return pwd_context.verify(plain_password, hashed_password)

def get_password_hash(password: str) -> str:
    """获取密码哈希"""
    return pwd_context.hash(password)

def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    """创建访问令牌"""
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
    return encoded_jwt

def decode_token(token: str) -> str:
    """解析令牌"""
    try:
        payload = jwt.decode(token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail="无效的认证信息"
            )
        return username
    except JWTError:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="无效的认证信息"
        )

async def get_current_user(
    token: str = Depends(oauth2_scheme),
    db: Session = Depends(get_db)
) -> User:
    """获取当前用户"""
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="无效的认证信息",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        username = decode_token(token)
        user = db.query(User).filter(User.username == username).first()
        if user is None:
            raise credentials_exception
        return user
    except JWTError:
        raise credentials_exception

async def get_current_active_user(
    current_user: User = Depends(get_current_user)
) -> User:
    """获取当前活跃用户"""
    if current_user.status != 1:
        raise HTTPException(status_code=400, detail="用户已被禁用")
    return current_user